<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>数据类型</title>
    <script>
        <!---->
        var a = 10;
        var b = 20;
        var temp = a;
        a = b;
        b =temp;
        alert(a);
        alert(b);
    </script>
</head>
<body>

</body>
</html>